KARACHI, Pakistan (AP) — Two blasts in Pakistan’s southern city of Karachi killed three people near the office of a political party critical of the Taliban, a police officer said, heightening tensions ahead of the country’s historic May 11 election.

Police officer Aamir Farooqi said the explosions late Saturday also wounded another 22 people. A spokesman for the Taliban, Ahsanullah Ahsan, claimed responsibility.

Pakistan has been experiencing a wave of violence connected to historic elections scheduled for next Saturday, mostly at the hands of Taliban militants targeting various political parties and their candidates. The vote will be the country’s first transfer of power from one elected civilian government to another.

Farooqi said the explosions went off near the offices of the Muttahida Qaumi Movement, the biggest political party in the city. It is one of three liberal, secular parties that have been targeted by Taliban militants across the country, likely due to their support for military action against militants that operate from Pakistan’s tribal areas bordering Afghanistan.

It was the second day in a row that the Muttahida Qaumi Movement found itself under attack. Gunmen Friday riding on a motorcycle killed a prominent party activist from the political party.

Also on Friday in Karachi, gunmen riding a motorcycle shot to death a parliamentary candidate from the Awami National Party, and his 6-year-old son.

The Awami National Party has been repeatedly targeted by the Taliban because of its opposition to the militants.

No one claimed responsibility for the Friday attacks.

Gunmen in Islamabad on Friday also killed the lead Pakistani prosecutor in two high-profile cases — the assassination of former Prime Minister Benazir Bhutto, and the brutal assault on civilians in Mumbai.

Nobody claimed responsibility for the killing of Chaudhry Zulfikar Ali, but his work put him in frequent conflict with militants. Ali was gunned down while he was driving to court in the normally quiet capital.